This invention discloses a method and related apparatus for saving a tooth which has been exarticulated, or knocked out.
Exarticulation of a tooth, also known as an avulsion, occurs when the entire tooth is forcefully and completely knocked out of its socket. Tooth exarticulation is quite common, especially among children. Exarticulation can result from falls, violence, or other causes. It is possible to save an exarticulated tooth, but only if the proper procedures are followed. Due to public ignorance, these procedures are seldom followed. When the exarticulated tooth is brought to a dentist, it is often too late to save the tooth.
All teeth have two main components, namely the crown and the root. The crown is the portion of the tooth that protrudes from the gum, and is normally the only visible part of the tooth. The root is the portion of the tooth embedded in the gum. The entire tooth root is surrounded by the periodontal membrane, also known as the periodontal ligament. The periodontal membrane is a soft, ligamentous material which connects the tooth to its bony socket. The periodontal membrane surrounds the entire root, but does not extend onto the crown.
If the periodontal membrane of an exarticulated tooth has not been substantially damaged, and if its cells are still alive, the tooth can be successfully reimplanted in its socket. After several days, the tooth will become naturally reaffixed to the socket. But if the cells of the membrane have died, the tooth is lost.
It has been known that, if an exarticulated tooth is stored in a proper medium, its periodontal membrane can be preserved, and the tooth can be saved. Various experiments have been done to determine which media are best for storing an exarticulated tooth. One article describing such experiments is "Milk and Saliva as Possible Storage Media for Traumatically Exarticulated Teeth Prior to Replantation", by L. Blomlof, Swedish Dental Journal, vol. 5, Supp. No. 8, pages 1-26 (1981). As indicated by the title, the article describes experiments which tested the effectiveness of milk and saliva as storage media for exarticulated monkey teeth. Both of these naturally-occurring media were found to be effective in promoting the vitality of the cells of the periodontal membrane.
The above-cited article also reports the results of experiments with artificial storage media. The medium that performed best in most of the experiments is the solution known as "Eagle's medium". Eagle's medium was first described in the article by M. Eagle, entitled "Amino acid metabolism in mammalian cell cultures", in Science, vol. 130, pages 432-437 (1959). Eagle's medium has been modified by others, and is available commercially from various sources.
The other artificial medium which has been shown effective in preserving an exarticulated tooth is the Hanks Balanced Salt Solution. This solution was also used successfully in the experiments reported in the above-cited article.
Other experiments on the preservation of monkey teeth in Eagle's medium have been reported in "Periodontal and Pulpal Healing of Monkey Incisors Preserved in Tissue Culture Before Replantation", by J. O. Andreasen et al, in the International Journal of Oral Surgery, vol. 7, pages 104-112 (1978). And the Hanks solution has been further tested, and found to be effective, in experiments reported in the article by L. Blomlof et al, entitled "Effect of Storage in Media with Different Ion Strength and Osmolalities on Human Periodontal Ligament Cells", in the Scandinavian Journal of Dental Research, vol. 89, pages 180-7 (1981).
In theory, it is thus comparatively easy to preserve an exarticulated tooth, and then to reimplant it. Unfortunately, exarticulation of a tooth is a traumatic experience for the victim. If the victim is a child, the trauma can be equally severe for the parent as well. Neither parents nor children are usually well-informed about how to preserve a tooth in this kind of emergency. Very often, by the time the tooth has been carried to a dentist, the cells of the periodontal membrane have died, and it is too late to save the tooth.
The present invention provides a simple method for saving an exarticulated tooth, and also provides an apparatus which is especially useful in practicing the method. The invention makes it possible for the general public to apply the above-described scientific findings for practical benefit.